Patients are randomly allocated for either perioperative SDD (intervention group) including standard antibiotic prophylaxis or standard treatment (including standard antibiotic prophylaxis alone) (control group). The solution containing SDD is orally taken 4 times daily, starting 3 days before surgery and continued until normal bowel passage or at least 3 days after surgery. Both groups receive a single preoperative intravenous dose of 1000 mg Cefazoline and 500 mg Metronidazole, which is the current standard antibiotic prophylaxis.